To get sound working the the U300/U305 you will need to add the following line to your /etc/modprobe.conf (or your distribution's equivalent) file:
options snd-hda-intel model=ref position_fix=1
However it's possible you already have a line that starts with options snd-hda-intel, in that case append model=ref position_fix=1 to the end of that line. Note: this procedure is not required with MDV2008.0 and the U305-S7448 (and probably others). Sound works out of the box
Working with Ubuntu Gutsy, a fix must be done, which is described here.

Just for grins, why don't you try this:
http://www.murga-linux.com/puppy/viewtopic.php?t=42553
This Puppy has an older kernel, but is always updated with the latest stuff.
Latest version is always posted at top of page 1.
(With this one, NTFS partitions must be mounted with Mut or Pmount for read / write capability.)

Oddly enough, when I zapped the Vista partition to EX4 and installed a fresh Puppy there, the sound icon appeared and sound worked. I made all the alsa files read-only, made backup copies, and turned off the computer.
When I turned it back on, I still had sound and an icon. No idea why, since that didn't happen with the first install.
Might just zap the first puppy install and use the new one rather than mess with things again.
Thanks,
Ed

[quote="Ed Howdershelt"]It's a Toshiba Satellite U305-S5097, made around 2007, yet the latest top Linux distros seem unable to make the sound card work.
Google hasn't turned up much that's useful.
I'd prefer to run it with Puppy Linux or Mint, but above all, I'd prefer to run it without Windows.
Any ideas?
Ed[/quote]

I happened to discover that the bios was changing its settings for no apparent reason and looked into that. Apparently there have been a couple of bios updates since the lappie's debut.
I haven't seen this kind of problem since I messed with the Columbia PC-XT back in 1983. Had to periodically tell their bios to restore defaults.
So I tried that and suddenly I had sound again.
The sound lasted through three boots, then went out. I checked the bios and found it had again changed itself.
I would have had to install XP to use the downloadable bios updates and they didn't seem to address either unwanted changes or sound.

SO... I sold the lappie to a local tech who seemed to think the bios issue was a non-issue.
He rather confidently installed Win7 on it, played some tunes, and called the problem fixed.
I told him to reboot it a few times just to be sure. He did so.
The sound went out after boot #3.
Resetting the bios defaults brought it back.
He downloaded the bios updates and ran them, then rebooted. The sound was out again.
Resetting the bios brought it back.
Rather than say 'Toldja so,' I said goodbye.

Too bad. It had a nice screen and it was fairly quick, but I like having my tunes playing while I work.
Anyway, thanks for all the help and suggestions here.
Ed
Ed Howdershelt - Abintra Press
Science Fiction & Semi-Fiction
http://www.AbintraPress.com

There are two batteries in every laptop, and one in every desktop. Most folks don't know about the extra one in each. It's a battery that keeps the BIOS working, and yours, while not properly dead, was on its way out.

That is a common source of BIOS corruption.

...oh, and the replacement batteries are less than $10 usually, although you have to disassemble the laptop to get to 'em. (Desktops almost universally use a CR2032 coin cell, although early Pentium 1 systems [and older] used a lithium rechargeable can that liked to go BANG! at the most inopportune of moments...)_________________

[quote="starhawk"]I bet I know what was going on... you bought this system used, right?
There are two batteries in every laptop, and one in every desktop. It's a battery that keeps the BIOS working, and yours, while not properly dead, was on its way out. That is a common source of BIOS corruption.
[/quote]

Could be, I guess, but I did check the CMOS battery before I decided to let the lappie go. 3v, apparently good.
Doesn't matter.
I'm back in FL and the laptop stayed in Iowa.
Ed
Ed Howdershelt - Abintra Press
Science Fiction & Semi-Fiction
http://www.AbintraPress.com